Short answer: wedi makes waterproof building boards, level-access shower trays, ready-made benches and seamless wall surfaces. Sauna Dekor specifies and installs them under the tiles and mosaic of the steam rooms, hammams and wet areas it builds; the products are wedi's.
In a steam room or hammam the waterproofing is the part nobody sees and nobody can put right later. wedi boards are used as the substrate on walls, ceilings and benches; joints and penetrations are sealed with wedi system components so the board, the tray and the bench work as one waterproof whole.
wedi divides wet rooms into water impact classes under DIN 18534 and publishes how its system is applied in each. See our steam rooms, how a steam room is built and hammams.

wedi wall elements
wedi functional units
wedi Fundo shower tray
wedi Fundo Top — linear drain
wedi Fundo Top — point drain
wedi I-Board Top
wedi Sanbath Flex washbasin
wedi Sanbath washbasin
wedi Sanbath Modular washbasin
wedi Sanbath Wave bathtub
wedi Sanoasa bench and lounger
wedi Sanoasa Top bench
wedi Sanoasa Top corner seat
wedi Sanwell Top niche surface
wedi Top Wall
wedi building board
wedi bonding system
wedi Fundo Primo
wedi Fundo Plano
wedi Fundo Integro
wedi Fundo Ligno Plus
wedi Fundo Borgo
wedi Fundo Trollo
wedi Fundo Nautilo
wedi Fundo Solido
wedi Fundo Riofino
wedi Fundo RioLigno
wedi Fundo Flex
wedi ModularSpa
wedi 620 sealant
wedi 520 sealing slurry
wedi Fundo sealing set
wedi Tools wall sealing set
wedi Tools shower tray sealing set
wedi Tools sealing tape, corners and gaiters
wedi Subliner Dry
wedi Subliner Flex
wedi Subliner Dry and Flex
wedi Tools joint reinforcement tape
wedi Tools bathtub sealing tape
wedi Tools cut-resistant tape
wedi Fundo substructure elements
wedi Fundo sloping board
wedi Fundo Solido extension board
wedi Fundo point drains
wedi Fundo linear drains
wedi Fundo drain grids
wedi Fundo channel frames and covers
wedi Fundo Discreto
wedi Fundo profiles and slope wedges
wedi Fundo sealing corners
wedi Tools edge strips